1. Field of the Invention
The invention is directed to a gas bearing comprising a bearing member formed of sintered grains and wherein at least one bearing surface layer is provided.
2. Description of the Prior Art
Numerous publications are concerned with gas bearings whose bearing members are formed of sintered material.
A fundamental discussion of such bearings may be found in an article by "Schmidt" (wt-Z including Fertig. 61 (1971), pp. 616-617). Beyond this, German No. A 31 10 712 discloses porous air bearings having intentionally compressed surfaces.
These publications are only cited as examples of the extensive prior art.
Various types of porous gas bearings have been known in practice.
(a) Gas bearings are known wherein the feed air is throttled given streams through the full sintered surface having an overall lower porosity. The full resistance is constant and high in the overall material. Very high tolerance demands of the sintered blank thus result if the bearing surface is to be subjected to little processing.
Sintered metals and artificial carbon are employed as initial materials.
(b) Gas bearings are known wherein feed air is throttled at the bearing surface. In order to achieve this throttling, the pre-processed bearing surfaces of the sintered material are compressed by grinding with loose grain under pressure. Only the entire bearing surface can thus be simultaneously processed. No reliable statement with respect to the residual thickness remaining after the grinding, and with respect to the mechanical stability of the uppermost grain layer can be made. The remaining throttle openings are non-uniformly distributed at the bearing surface. Residues of the loose grinding grain can be embedded in the sintered material in the region of the bearing surface.
(c) Gas bearings are known wherein thin nozzle plates are applied as throttle elements on a porous base material serving the purpose of feed air supply.